1. Field of the Invention
This invention relates to a developing method and a developing unit of a substrate.
2. Description of the Related Art
In a process of photolithography in a fabricating process of a semiconductor device, for example, a resist solution is coated onto a surface of a wafer, and a resist coating for forming a resist film, an exposure for exposing the wafer according to a pattern, a developing for developing the exposed wafer and so on are operated to form a predetermined circuit pattern on the wafer.
In the developing for developing the wafer as described above, a method for supplying a developing solution with a developing solution supply nozzle which is in a slimline shape and is provided with a plurality of supplying holes of the developing solution scanning above the wafer is often used.
In this method, the wafer is first mounted on a mounting table, and the developing solution supply nozzle which is on standby at a home position (standby position) outside one end of the wafer scans above the wafer while supplying the developing solution, and stops supplying the developing solution when the developing solution supply nozzle moves to the other end of the wafer, so that the developing solution is supplied onto an entire surface of the wafer. Thereafter, the developing solution supply nozzle is returned back to a standby position, that is, the home position from the other end of the wafer by passing above the wafer. The developing solution supply nozzle always returns to the home position because a washing mechanism for washing the developing solution supply nozzle is provided at the home position outside one end of the wafer.
Then, after a predetermined time is passed and the developing is complete, pure water is supplied onto the wafer to wash the developing solution from the wafer W.
However, in the aforementioned developing method, the developing solution supply nozzle passes above the wafer again after the developing solution is supplied onto the wafer, and hence there is a possibility that the developing solution drips from the developing solution supply nozzle onto the wafer. If the developing solution is dripped onto the wafer, the developing solution of this dripped spot contains a different concentration, and further, there is apprehension that dirt which is attached to the developing solution supply nozzle may be included therein when dripping, which may result in developing defect, line width defect, shape failure of the wafer and so on.
Moreover, if pure water is supplied onto the wafer immediately after a predetermined time is passed to complete the developing, so-called pH shock which is occurred in supplying a liquid of a large difference in pH value may occur to generate an impurity. This may result in developing defect.
The present invention is made in view of these points, and its first object is to provide a developing method for preventing a mistaken drip of a developing solution onto a wafer which is already supplied with the developing solution and a developing unit provided with a function therefor, in a developing method for supplying the developing solution onto the wafer while scanning.
A second object of the present invention is to prevent an occurrence of so-called pH shock in the developing.
In view of the aforementioned first object, according to a first aspect of the present invention, the present invention is a method for developing a substrate by supplying the developing solution from a developing solution supply nozzle onto a surface of the substrate mounted on a predetermined position, comprising the steps of: moving the developing solution supply nozzle from a standby position of the developing solution supply nozzle outside one end of the substrate to at least the other end of the substrate without supplying the developing solution, and moving the developing solution supply nozzle thereafter from the other end to at least the one end while supplying the developing solution.
Thereby, the developing solution is not supplied when the developing solution supply nozzle moves from the standby position of the substrate to the other end of the substrate, and the developing solution is supplied when it moves from the other end of the substrate to the standby position, so that the developing solution supply nozzle which is used once and has a possibility of the drip of the developing solution never passes above the substrate. Therefore, it is prevented that, because of the developing solution which is mistakenly dripped from the developing solution supply nozzle onto the wafer before and after supplying the developing solution, this dripped spot contains a different concentration of the developing solution, or the dripped developing solution including dirt and the like adheres to the substrate, which eliminates the possibility of developing defect and so on.
According to a second aspect of the present invention, the present invention is the method for developing the substrate by supplying the developing solution from the developing solution supply nozzle onto the surface of the substrate mounted on the predetermined position, comprising the step of: mounting the substrate on the predetermined position, between the steps of moving the developing solution supply nozzle from the standby position of the developing solution supply nozzle outside the predetermined position to at least the other end of the substrate without supplying the developing solution, and moving the developing solution supply nozzle from at least the other end to at least one end while supplying the developing solution.
Thus, the step of mounting the substrate on the predetermined position is included between the aforementioned steps so that the substrate is carried into a process unit after the developing solution supply nozzle moves to the other end of the substrate, and hence the developing solution supply nozzle never passes above the wafer except when supplying the developing solution. Therefore, the possibility that the developing solution is mistakenly dripped from the developing solution supply nozzle onto the wafer is completely eliminated.
According to a third aspect of the present invention, the present invention is the method for developing the substrate by supplying the developing solution from the developing solution supply nozzle onto the surface of the substrate mounted on the predetermined position, comprising the steps of: moving the developing solution supply nozzle from the standby position of the developing solution supply nozzle outside one end of the substrate to at least the other end of the substrate while supplying pure water, and moving the developing solution supply nozzle thereafter from at least the other end to at least the one end while supplying the developing solution.
Thereby, pure water is supplied when the developing solution supply nozzle moves from the standby position of the substrate to the other end of the substrate, and the developing solution is supplied when it moves from the other end of the substrate to the standby position, so that the developing solution supply nozzle which has the possibility of the drip of the developing solution does not pass above the substrate which is already supplied with the developing solution, in contrast to the conventional art. Therefore, if the developing solution is mistakenly dripped from the developing solution supply nozzle after supplying the developing solution onto the substrate, the dripped developing solution never drips onto the wafer because it does not pass above the substrate. Therefore, it is prevented that, because of the developing solution which is mistakenly dripped from the developing solution supply nozzle onto the wafer after supplying the developing solution, this dripped spot contains the different concentration of the developing solution, or the dripped developing solution including dirt and the like adheres to the substrate. Further, when the developing solution is directly supplied onto the substrate, there is apprehension that developing defect such as partial unevenness of the developing may occur because minute air bubbles which exist in the developing solution and minute air bubbles which is generated when the developing solution adheres to the substrate, but these cases can be prevented by supplying pure water onto the substrate before supplying the developing solution thereon.
According to a fourth aspect of the present invention, the present invention is a developing unit of the substrate for supplying the developing solution onto the substrate with the developing solution supply nozzle moving toward a predetermined direction above the substrate, wherein the developing solution supply nozzle includes a developing solution supply hole for supplying the developing solution and a pure water supply hole for supplying pure water individually along the predetermined direction, and wherein the pure water supply hole is structured to supply pure water when moving to a reverse direction of the predetermined direction, and the pure water supply hole is placed in a forward side of a moving direction in supplying pure water.
Thus, the pure water supply hole and the developing solution supply hole are provided individually, in which the pure water supply hole for supplying pure water while moving toward the reverse direction of the predetermined direction is provided to be placed in the forwarder side of the moving direction than the developing solution supply hole so that the developing solution supply hole always passes above the substrate after pure water is supplied thereon. Thereby, if the developing solution is dripped from the developing solution supply hole, it is dripped onto a pure water film, not onto the substrate directly, and hence developing defect or the like due to the drip of the developing solution is prevented.
According to a fifth aspect of the present invention, the present invention is the developing unit of the substrate for supplying the developing solution onto the substrate with the developing solution supply nozzle moving toward the predetermined direction above the substrate, wherein the developing solution supply nozzle includes the developing solution supply hole for supplying the developing solution and the pure water supply hole for supplying pure water individually along the predetermined direction, and wherein the pure water supply hole is structured to supply pure water when moving to the reverse direction of the predetermined direction, and the pure water supply hole is placed in a backward side of the moving direction in supplying pure water.
Thereby, when the developing solution supply hole supplies the developing solution while moving toward the predetermined direction, the developing solution supply hole is placed in the backward side of the moving direction with respect to the pure water supply hole. Namely, contamination of the other supplying hole by a supplying process solution can be prevented because the supply hole which supplies the process solution is always placed in the rear side of the moving direction.
According to a sixth aspect of the present invention, the present invention is the developing unit of the substrate including the developing solution supply nozzle for moving above the substrate and for supplying the developing solution onto the substrate, comprising: washing tanks for washing the developing solution supply nozzle outside both ends of the substrate, respectively.
This washing tank is not limited to the one which simply stores a washing solution in a tank, but the one which is structured to receive a part of the developing solution supply nozzle for washing it is also included.
Thus, by providing the washing tanks at both sides outside the substrate, a supplying means can be washed every time when the developing solution supply nozzle reaches the respective outer portion at both sides of the substrate, in a case where, for example, the developing solution is supplied onto the substrate by its reciprocating movements above the substrate. Therefore, it is not necessary to return from the other end to one end for washing after, for example, it moves from one end to the other end for supplying the developing solution. That is, after supplying the developing solution, the developing solution supply nozzle is unnecessary to move above the substrate for the washing. Thus, the developing solution supply nozzle having the possibility of dripping the developing solution does not pass above the substrate, so that developing defect or the like due to the drip of the developing solution is prevented.
In view of the second object of the present invention, according to a seventh aspect of the present invention, the present invention is a method for developing the substrate by supplying the developing solution onto an entire surface of the substrate mounted on the predetermined position, comprising the steps of: supplying a developing solution onto the substrate with the lower concentration than that of the aforementioned developing solution, after completion of the developing for a predetermined time after the developing solution is supplied, supplying the developing solution with the lower concentration onto the wafer by gradually decreasing its concentration, and supplying pure water subsequently onto the substrate.
According to an eighth aspect of the present invention, the present invention is the developing unit of the substrate for supplying the developing solution onto the substrate with the developing solution supply nozzle moving toward the predetermined direction above the substrate, wherein the developing solution supply nozzle includes the developing solution supply hole for supplying the developing solution and the pure water supply hole for supplying pure water individually along the predetermined direction, and wherein a supplying amount of the developing solution from the developing solution supply hole and a supplying amount of pure water from the pure water supply hole are adjustable.
According to the ninth aspect of the present invention, the present invention is the developing unit of the substrate for supplying the developing solution onto the substrate with the developing solution supply nozzle moving toward the predetermined direction above the substrate, wherein the developing solution supply nozzle includes the developing solution supply hole for supplying the developing solution and the pure water supply hole for supplying pure water individually along the predetermined direction, and wherein the developing solution supply hole is structured to be able to supply the developing solutions with a plurality of different concentrations.
According to the present invention, there is no possibility of the occurrence of xe2x80x9cpH shockxe2x80x9d because pure water is not supplied all at once as in the conventional art. Such a process can be operated after a predetermined developing solution on the substrate is cleared off by rotating the substrate after the developing, or the supplying of the developing solution with the low concentration can be started at the same time with the clearing off.
Further, according to the present invention, the developing solution supply hole for supplying the developing solution and the pure water supply hole for supplying pure water are included individually along the predetermined direction, and the supplying amount of the developing solution from the developing solution supply hole and the supplying amount of pure water from the pure water supply hole are adjustable. Thereby, for example, after a predetermined developing, the developing solution is supplied from the developing solution supply hole and pure water is simultaneously supplied from the pure water supply hole so that the developing solution with the low concentration can be supplied onto the substrate, and further, since each of supplying amount is adjustable, the supplying amount of pure water is gradually increased, or the supplying amount of the developing solution is gradually decreased, or both of them are performed to finally supply only pure water, which makes it possible to realize a process in which the developing solution with the low concentration is supplied while gradually decreasing its concentration and finally, only pure water is supplied.
Moreover, according to the present invention, the developing solution supply hole is structured to be able to supply the developing solutions with the plurality of different concentrations, so that, for example, the developing solution with the decreasing concentrations can be supplied in order, and the supplying of the developing solution from the developing solution supply hole can be stopped at last to supply only pure water from the pure water supply hole.